Rail truck bolster



April 16, 1946. E. H. PIRON' 2,398,394

' RAIL TRUCK BOLSTER Filed March. 12, 1943 2 Sheets-Sheet 1 [M 4 bf IOIROM April 16, 1946. E. H. PIR QN RAIL TRUCK BOLSTER Filed March 12, 1945 2 Sheets-Sheet 2 I (ll Patented Apr. 16, 1946 2,398,394 RAIL TRUcK BOLSTER Emil H. Piron, New York, N. Y., assignor to Transit Research Corporation, New York, N. Y., a corporation of New York Application March 12, 1943, Serial No. 478,951

4 Claims.

This invention relates to rail trucks and particularly to the bolsters therefor and has for its object to provide an improved bolster assembly by the use of which the usual design of truck may be substantially simplified. i

It has been the general practice to support truck bolsters from an upper frame carried on springs supported from a lower unsprung frame composed of the axle housings and side rails connecting the axle housings. Street cars are run at moderate speeds, often over tracks in poor aligned vertically as well as horizontally. The result is that occasional sharp impulses of large amplitude and low frequency, super-imposed upon weak impulses of small amplitude and high frequency are transmitted to the lower frame. If these impulses are to be prevented from being transmitted to the car body the bolster must be supported upon the lower frame by relatively soft springs supplemented by some means of absorbing the energy of the large impulses so as to prevent continuation of body oscillations once set up. It is the object of this invention to provide a bolster which will meet these conditions. More particularly it is the object to eliminate the upper frame and provide a bolster which will be supported directly by springs resting on the lower frame, which therefore becomes the Only frame, and to provide means in the form of articulated joints between the bolster and the springs. In this manner the energy of large impulses is absorbed without the use of an upper frame with the result that the number and weight of parts are reduced, clearances are increased, and accessibility to parts for inspection or replacement is greatly improved,

The requirements are thus that. the bolster be provided with a soft suspension spring in order to reduce the effect of small impulses of relatively high frequency and that the same suspension be capable of absorbing the energy of violent im pulses of large amplitude and relatively low frequency thereby preventing that energy from being transferred into potential energy which could cause violent oscillations of the body.

More particularly it is an object of the invention to provide a bolster directly supported from the frame by a set of springs by means of trunnions as will become hereinafter more fully apparent with reference to the accompanying drawings in which Figure'l is a plan view of a rail truck equipped with my improved bolster and. bolster suspension.

condition and on rails which may be improperly Figure 2 is an enlarged plan view of the bolster, and

Figure 3 is a vertical section taken along the line 3-3 of Figure 2. v

More particularly, Figure 1 shows a rail truck in top plan view in which 1 indicates the side rails of the frame, 2 refers to the axle housings and 3 to the wheels. The driving motors 8 are supported from the frame by the cross beams I and 5. The truck to this point might be any rail truck but, as illustrated, is similar to the truck shown and described in my co-pending application Serial Number 414,589 filed October 11, 1941.

Supported on the side rails l are four springs l for supporting the bolster assembly composed, first, of a bolster 8 having a center bearing 9 and a center bearing pot Ill. The bolster terminates at each end in a bearing ll, through which a pin l2 extends. The pins I2 are supported in spring receivers l3 into which the upper ends of the springs I extend. The receivers are connected in pairs by the members M.

It will thus beseen-that the bolster assembly is generally of H shape with the center bearing 9 being at the center of the cross-bar of the H. A spring 1 supports each end of each upright of the H and each upright is hinged to the cross-bar for relative rotation through a, vertical arc. The are is normal to the direction of travel of the truck. In order to stabilize the springs I cylindrical members I5 of slightly less diameter than the inner diameter of the springs are secured to the side rails l. The clearance can be varied according to the amount of lateral movement desired between the bolster assembly and the main frame.

As there is friction between bearing II and pin l2 rotation between these parts does not take place unless large impulses are transmitted to them and the H shaped bolster assembly reacts to small impulses as a solid assembly. as long as the impulses are so small that they are not sufiicient to distort the springs I through the clearance between them and parts l3 and 15, such springs react as purely elastic elements, without friction, in" the proper manner to prevent the transmission of impulses of small amplitude and high frequency to the bolster and body assembly. p

However, when the amplitude and intensity of an impulse is large and suiilcient to distort the spring sideways, to an amount sufllcient to establish contact between parts 15 and the spring, pin I2 is caused to rotate against its friction in bearing II and this friction absorbs the energy Further,

of the large impulse, instead of returning. its energy to continue or duplicate the started oscillation as would be the case with non-frictional resistance.

It will be seen that all driving and retarding forces between the truck frame and the bolster are transmitted by the springs I. When acceleration and deceleration is suflicientto deflect the springs into contact with the flanges l5 these flanges serve the function of a transom since no transom is provided.

I desire to be extended protection within the scope of the appended claims, wherein What I claim is:

1. A rail truck bolster assembly of H-shape comprising a bolster proper terminating at each end in abearing member, spaced spring receivers having a bearing member therebetwe :n for operating engagement with the bearing member of said bolster proper, said spring receivers being of inverted cup shape each adapted for the seating of a coil spring therein, said receivers each having depending ears to which said bearing members are secured, whereby said bearing members are all substantially below the top of said springs, said bolster proper having a center bearing pot intermediate the ends thereof, the axis of which substantially parallels the axis of said spring receivers when the bolster assembly is in normal position.

2. A rail truck bolster assembly of H-shape comprising a bolster proper terminating at each end in a bearing member, spaced spring receivers havin a bearin member therebetween for operating engagement with the bearing member of said bolster proper, said spring receivers being of inverted cup shape each having a coil spring seated therein, said receivers each having a depending ear to which its respectiv bearing member issecured whereby said bearing members are all substantially below the tops of said springs, a bottom supporting member for each of said springs having a motion limiting flange of slightly less diameter than the inside diameter of said springs arising therefrom and extending upwardly into said springs above the level of aid bearing members, said flanges serving the function of a transom, said bolster proper having a center bearing receiving opening intermediate the ends thereof, the axis of which substantially parallels the axes of said spring receivers when thebolster assembly is in normal position.

3. A rail truck comprising a mainframe, a bolster assembly comprising a bolster, spaced spring receivers at each side-of each end of said bolster hingedly connected to said bolster, and springs all of which are supported by said main frame and each of which supports one of said receivers from said frame, said springs being of the coil type and each having a motion limiting stop arising from said frame and projecting thereinto, said stops having slight clearance with the interiors of their respective springs and serving the functions of a transom.

4. In a rail truck, a frame, a bolster, springs supporting said bolster from said frame, said springs being adapted to deflect freely under relative vertical movements and under small relative lateral movements between said bolster and said frame, stop means individual to each of said springs limiting the relative lateral movements of said springs, and friction bearings supporting said bolster on said springs operative to permit relative movement between said bolster and said frame after contact of said springs with said stops, said stops extending internally of said springs from the bottom thereof upwardly for at least half the height of said springs.

EMlL H. PIRON. 

